#include <iostream>
#include <cstdio>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <string>
#include <cstring>
#include <cstdlib>

#define N 2
#define NUM 1024
using namespace std;

void Writer(int wfd)
{
    string s = "this is your child";
    pid_t myid = getpid();
    int number = 0;

    char buffer[NUM];
    while(1)
    {
        //buffer[0] = '\0';
        sleep(1);
        buffer[0] = 0;
        snprintf(buffer,sizeof(buffer),"%s-%d-%d",s.c_str(),myid,number++);
        write(wfd,buffer,strlen(buffer));
    }
}

void Reader(int rfd)
{
    char buffer[NUM];
    int cnt = 0;
    while(1)
    {
        sleep(1);
        buffer[0] = 0;
        ssize_t n = read(rfd,buffer,sizeof(buffer));
        if(n > 0)
        {
            buffer[n] = 0;
            cout << "parent get a message[" << getpid() << "]# " << buffer << endl;
        }
        else if(n == 0) 
        {
            printf("parent read file done!\n");
            break;
        }
        else break;
        if(cnt++ == 5)
        {
            break;
        }
    }
    
}

int main()
{
    int pipefd[N] = {0};
    int n = pipe(pipefd);
    if(n < 0)
    {
        return 1;
    }

    pid_t id = fork();

    if(id < 0)
    {
        return 2;
    }
    else if(id == 0)
    {
        //child
        close(pipefd[0]);
        Writer(pipefd[1]);
        close(pipefd[1]);
        exit(0);
    }
    else{
        //parent
        close(pipefd[1]);
        Reader(pipefd[0]);
        close(pipefd[0]);
        cout << "father close read fd: " << pipefd[0] << endl;
        sleep(5);
        int status = 0;
        pid_t rid = waitpid(id,&status,0);
        if(rid < 0)
        {
            return 3;
        }
        cout << "wait child success: " << rid << " exit code: " << ((status>>8)&0xFF) << " exit signal: " << (status&0x7F) << endl;
        sleep(5);
        cout << "parent quit" << endl;
    }
    
    return 0;
}